1. Field of the Invention
The present invention relates to a torque sensor, to a continuously variable transmission that includes a torque sensor, as well as to a method for controlling a torque sensor associated with a continuously variable transmission.
2. Description of the Related Art
Torque sensors, continuously variable transmissions, as well as methods for controlling torque sensors and continuously variable transmissions are already known.
The invention is directed to a torque sensor with a different design, to a continuously variable transmission with a different design, as well as to a different method for controlling a torque sensor and/or for controlling a continuously variable transmission.
In accordance with one particular aspect, the invention is directed to a more consistent continuously variable transmission having a torque sensor.
In accordance with one particular aspect, the invention is directed to a torque sensor as well as to a continuously variable transmission that have a simpler design and that ensure higher operational reliability.
In accordance with one particular aspect, the invention is directed to a method for operating a torque sensor and/or a continuously variable transmission that can be conducted with little effort and high operational reliability.
The objects of the invention are achieved with a torque sensor that displays at least one of the features that are explained in the following description and claims, or that are shown in the drawing figures.
The objects of the invention are furthermore achieved with a continuously variable transmission that has at least one of the features that are explained in the following description or claims, or that are shown in the drawing figures.
The objects of the invention are furthermore achieved with a method for controlling a torque sensor, or for controlling a continuously variable transmission having a torque sensor that has at least one of the features that are explained in the following description or claims, or that are shown in the drawing figures.
The invention is directed in particular to a torque sensor that has at least one input member as well as at least one output member, and a transmitting element that is arranged between the input member and the output member and which can at least be moved in the radial direction. The transmitting element is arranged particularly in the axial direction between the input member and the output member of the torque sensor. The transmitting element can transmit power and possibly torque between the input member and the output member. Torque can be applied to the output member externally, wherein the transmitting element causes the output member to generate a pressing force.
In accordance with the present invention, the input member is in particular a component that is rotatably arranged, and the output member is in particular a component that is arranged in a fixed manner in relation to a shaft. The invention, however, should not thereby be limited. In accordance with the present invention, the input member preferably consists of a disk-like component, as does the output member. In accordance with the present invention, the output member may be coupled with a disk and/or a conical disk of a continuously variable transmission, or it can be designed as one piece together with the disk.
The transmitting element in accordance with the invention is particularly a component that is movably arranged relative to the output member and/or relative to the input member. The transmitting element can have the design of a ball, a roller, a spreader body, or other design.
The driving power generated by the output member in accordance with the present invention should be interpreted particularly as power that is applied onto the output member and can be passed on to surrounding components and preferably is linear.
The transmitting element""s ability to move in the radial direction is designed in accordance with the present invention in such a way that the transmitting element can also be moved in the circumferential direction. In accordance with the present invention, it is particularly provided that the transmitting element is additionally movably arranged in at least one other direction relative to the input and/or output member, and particularly in the circumferential direction and/or in the axial direction.
In accordance with the invention there is particularly provided a torque sensor for a continuously variable transmission that can transmit torque in a frictionally-engaged manner. The power that is transmitted through at least one transmitting element between the input member and the output member has a component of power acting in the circumferential direction and a component of power acting in the axial direction. The continuously variable transmission is equipped with sets of disks, between which torque can be transmitted in a frictionally-engaged manner through an endless, torque-transmitting means. The power that is transmitted between the endless, torque-transmitting means and the respective disk set and/or the respective disks also has a component of power that acts largely in the circumferential direction. The torque sensor is associated with at least one of those disk sets. In accordance with the invention, the power component acting in the circumferential direction, for the power that is transmitted between the input member and the output member of the torque sensor, is proportional to the power component acting in the circumferential direction that is transmitted by the disk set associated with the torque sensor between the endless, torque-transmitting means and that disk set. The proportionality factor between those power components acting in the circumferential direction is preferably equal to 1, so that the power component transmitted between the input member and the output member in the circumferential direction corresponds with the power component transmitted in the circumferential direction between the disk set that is associated with that torque sensor and the endless, torque-transmitting means.
In accordance with the invention, a torque sensor is provided that is equipped with an input member as well as an output member and a transmitting element that is arranged between the input member and the output member. The transmitting element is supported against a ramp of the input member and the output member, respectively, during the transmission of torque and/or power between those parts. Torque that is applied to the input member generates a pressing force on the output member.
For the purpose of torque transmission in a continuously variable transmission, the respective disk sets of that transmission are loaded by a pressing force, particularly an axially acting pressing force. As a function of the torque that is to be transmitted, and possibly as a function of the transmission ratio that is established during torque transmission, the necessary pressing forces that are required to be able to transmit the torque that is to be transmitted between the disk sets are available for each of the disk sets. In accordance with the inventionxe2x80x94both during a pushing operation as well as during a pulling operationxe2x80x94the same tracks and/or ramps that are arranged on the input member and/or the output member are acting, as are the same transmitting elements that are provided on the torque sensor, wherein the deviation between the pressing force generated by the torque sensor and the pressing force on the respective disk set required for torque transmission is largely identical during a pushing operation and a pulling operation. In accordance with the invention, preferably a feature is provided so that during a pushing operation as well as during a pulling operation, with a given torque that is supposed to be transmitted and/or a given transmission ratio, the same tracks and/or ramps of the torque sensor are used for generating the pressing force, without the deviation of the generated pressing force being different from the pressing force required on the respective disk set.
In accordance with the invention there is particularly provided a torque sensor where one or more transmitting elements transmit power between an input member and an output member of the torque sensor, wherein the torque load on the input member causes a pressing force to be generated on the output member, and wherein the position of the torque sensor is not dependent upon the direction of the load that is present on the torque sensor and/or on the continuously variable transmission associated with that torque sensor.
A preferred torque sensor in accordance with the invention is designed in such a way, and interacts with a continuously variable transmission in such a way, that the radial position of at least one of the transmitting elements is controlled as a function of the position of the endless, torque-transmitting means. In particular, the torque sensor is associated with a disk set of the continuously variable transmission, wherein the radial position of the transmitting element or elements is controlled as a function of the travel radius of an endless, torque-transmitting means on that disk set.
The transmitting element or elements of the torque sensor preferably assume the radial position that corresponds to the travel radius of the endless, torque-transmitting means on one of the disk sets. In a preferred embodiment, one torque sensor is provided per set of disks, wherein the transmitting element or elements associated with those torque sensors are basically arranged in a radial position that corresponds largely to the travel radius on the disk sets associated with those respective torque sensors.
Preferably, at least one transmitting element is restrictively guided. In a particularly preferred embodiment, the restricted guidance of the transmitting element is effected by ramps or tracks that are arranged on the input member or the output member of the torque sensor.
Predetermined movements of at least one disk set of a continuously variable transmission or of an endless, torque-transmitting means of that continuously variable transmission are preferably coupled with predetermined movements of a transmitting element of the torque sensor. In a particularly preferred embodiment, a predetermined relative adjustment of the disks of a disk set of the continuously variable transmission, particularly in the axial direction, causes a transmitting element of a torque sensor to be moved at least also in the radial direction, in particular in such a way that an increase in the axial spacing of the disks of that disk set causes the transmitting element to be moved radially inward, and that a decrease in the axial spacing of the disks of the disk set causes the transmitting element to be moved radially outward.
In a particularly preferred embodiment, the radial position of a transmitting element of a torque sensor depends on the transmission ratio in a continuously variable transmission that is associated with that torque sensor, especially with a defined spacing between axes of the shafts of the continuously variable transmission, between which an infinitely variable transmission process can take place.
Preferably, at least one transmitting element of the torque sensor is moved along a ramp that is arranged on the input member and/or on the output member of the torque sensor, in such a way that each radial position of the transmitting element is allocated exactly one defined position of the ramp and/or track.
The travel tracks of two or more transmitting elements of a torque sensor are preferably coupled with each other at least in part, particularly via a retainer that may contain grooves. In a particularly preferred embodiment, grooves that extend basically in the radial direction are provided in such a retainer.
A preferred torque sensor in accordance with the invention is equipped with a retainer that holds at least one transmitting element, as well as at least one ramp that is arranged on the input member and/or output member of the torque sensor. In a particularly preferred embodiment, those ramps interact with the retainer and the transmitting elements in such a way that through a combination of the degrees of freedom that the transmitting elements have on the ramps on one hand, and the degrees of freedom that the transmitting elements have in the retainer on the other hand, it is ensured that the various transmitting elements have the same radial position, respectively.
In a particularly preferred embodiment, a ramp, and especially a ramp that is associated with an output member of the torque sensor and along which a transmitting element can travel, is connected with a conical disk or arranged on a conical disk, wherein that ramp possibly has the design of a recess in the conical disk.
The output member of the torque sensor is preferably designed as one piece together with a disk of the disk set that is associated with that torque sensor.
The torque sensor preferably has a ramp system whose ramps may have a constant slope.
In a particularly preferred embodiment the ramp system, and possibly the individual ramps or at least some of the individual ramps of the ramp system, has a constant slope, wherein it is preferably additionally ensured that the transmitting elements that can travel, particularly in contact, between or at least along a ramp of that ramp system of the torque sensor, each take on a position in the radial direction of that ramp system as the one in which an endless, torque-transmitting means is arranged in the radial direction on a conical disk set that is associated with that torque sensor.
The input member and the output member of the torque sensor and/or the ramp system are preferably arranged in such a way that they can move relative to each other, especially in the circumferential direction, and possibly in the axial direction. In a particularly preferred embodiment, at least one transmitting element that is arranged between the input member and the output member is guided along at least one ramp during a relative movement of those parts. That ramp is arranged on the input member and/or the output member.
During a relative movement between the input member and the output member the transmitting element preferably is in contact with at least one ramp, in a particularly preferred embodiment with all neighboring ramps.
In a preferred embodiment, at least one ramp is arranged on the input member and/or the output member, respectively, of the torque sensor and/or the ramp system, wherein interaction of those tracks with at least one transmitting element, and possibly with a retainer, determines the travel track of the transmitting element or elements during a relative movement of those ramps.
The lengthwise direction of at least one ramp that is provided on the input member and/or on the output member of the torque sensor preferably extends also in the radial direction in each position of that ramp. In a preferred embodiment, the lengthwise direction of the ramp extends in such a way that basically no areas exist that run only in the circumferential direction.
In a particularly preferred embodiment, at least one ramp of the torque sensor has a curved design. Preferably, at least one ramp or exactly one curved ramp is provided both on the input member and on the output member. In a preferred embodiment, a ramp that is arranged on the input member and/or on the output member has a spiral design. A ramp that is arranged on the input member and/or on the output member preferably extends from an area that is arranged largely radially in the center of that input member and/or that output member in a radially outwardly curved and/or spiral shaped manner, clockwise or counterclockwise. The curved ramp preferably has a constant curvature direction, i.e., is continuously left-curved or continuously right-curved. Tracks that are left-curved in certain sections and right-curved in certain other sections are also preferred.
In a preferred embodiment, the (partial) ramp system that is provided on the input member has a design that is identical to that of the (partial) ramp system provided on the output member when viewed from above. In a particularly preferred embodiment a (partial) ramp system that is provided on the input member has a design that is different from the (partial) ramp system that is arranged on the output member when viewed from above.
A ramp or a ramp system is preferably arranged on the input member as well as on the output member, with those ramps facing each other.
In a preferred embodiment, the position of the torque sensor and/or the position of the transmitting element or elements is basically clearly determined relative to the ramp system in a given position of the disk sets of a continuously variable transmission. In a particularly preferred embodiment, the transmitting element, or elements, always takes on the same position in the radial direction and/or relative to the respective tracks with equal and/or reproduced transmission ratios of the continuously variable transmission, particularly independently of its direction of rotation.
The input member, and/or the output member, of the torque sensor is preferably designed as one piece.
In the preferred embodiments of the invention, where it was mentioned that proportionality exists, the proportionality factor is smaller than 1, or equal to 1, or larger than 1.
In a particularly preferred embodiment a safety factor is utilized that offers additional safety that sufficient pressing force is always available. That safety factor can be an absolute increase, possibly in addition to the proportionality factor, or be taken into consideration in the proportionality factor, e.g., as a percentage increase.
In a particularly preferred embodiment those ramps of the torque sensor are designed in such a way that on one hand they extend at least in the radial direction of the torque sensor, and that on the other hand at least one of those tracks has a slope so that the output member is shifted axially relative to the input member when the transmitting element changes its position on the track and/or ramp.
It should be noted that a track and/or a ramp in accordance with the present invention should be interpreted particularly as an area of the input member and/or an area of the output member of the torque sensor or a ramp system, which can support one or several transmitting elements and through which those transmitting elements can possibly be exposed to load, wherein that track and/or ramp can have a profiled or non-profiled design and can have a slope or not have a slope.
The track or ramp may possibly have the design of a profiled recess, wherein in a preferred embodiment a transmitting element can travel along the ramp and/or track. The term track and/or ramp in accordance with the invention however should be interpreted in a broader sense, so that a track includes a longitudinal expansion or no longitudinal expansion. A track should be particularly interpreted as a channel-like area that is equipped with a triangular or rounded or rectangular or otherwise designed cross-sectional area, or a holding device for holding a transmitting element. A preferred embodiment furthermore is a design where a transmitting element in the shape of a ball is in one way retained on the input member or on the output member in a holding retainer that is also designated as a track and/or ramp, and where the other one of those parts contains a longitudinally extending track, e.g. a track that is designed as a profiled recess, along which the transmitting element can travel. In accordance with the invention, the term xe2x80x9ctrackxe2x80x9d is also used in the sense of a travel track and/or travel line, particularly relative to the transmitting element.
In accordance with the present invention in particular a track is a ramp and/or a ramp is a track, wherein the term track and/or ramp relates particularly to a track and/or ramp that is arranged on the input member or on the output member.
A ramp in accordance with the present invention should particularly also be understood as a ramp in the classical sense that contains along its lengthwise direction an inclination or slope that can be constant or that can vary along the lengthwise direction. In a particularly preferred embodiment, a torque sensor in accordance with the invention is equipped with a ramp that has a largely constant slope in the lengthwise direction.
The tracks and/or ramps that are arranged on the input member can have the same design or different designs compared with those that are arranged on the output member.
In accordance with the present invention a continuously variable transmission should be interpreted particularly as a transmission wherein torque is transmitted through an endless, torque-transmitting means, such as a chain or belt or similar. That continuously variable transmission preferably contains at least some of the following features: A preferred continuously variable transmission is equipped with an input disk set as well as an output disk set. Those disk sets are each equipped with two disks that can be moved relative to each other, especially in the axial direction, so that their spacing can be changed. In particular, the respective disks of a disk set are designed as conical disks that face each other at their tapered ends. In a preferred embodiment, torque is transmitted between those disk sets through frictional engagement between the respective disk set and the endless, torque-transmitting means. In a particularly preferred embodiment torque is transmitted through a plate-link chain, wherein the plate-link chain contains chain links that are connected with each other through link elements. The link elements are preferably designed in such a way that two rocker members that are associated with each other as well as with the same link elements, roll or ride against each other relative to that link element during a tilting movement of the adjacent chain links. At least one of those rocker members preferably extends sideways beyond the plate-link sets and can be supported on the disks and/or conical disks of the respective disk sets through frictional engagement, so that torque is transmitted between the respective conical disk sets and the plate-link chain via the rocker members that in particular engage with the links of the plate-link chain in a positive lock. The rocker members may be rounded or tapered or designed otherwise at their ends for that purpose. Within each chain link several plate links are arranged that are aligned parallel to each other or at an angle to each other or otherwise. The plate links within a chain link can be identical or have different designs. The plate links of different chain links can be identical or have different designs. Different chain links have identical or differing separations.
In accordance with the invention, a torque sensor for a continuously variable transmission is provided that can transmit torque in a frictionally-engaged manner. For the purpose of frictionally-engaged torque transmission via the continuously variable transmission, a pressing force is required that depends on the adjusted transmission ratio as well as the torque that is applied, and thus has a transmission-ratio-dependent portion and a torque-dependent portion. The torque sensor generates a pressing force that contains a power portion that is proportional to the transmission-ratio-dependent portion and/or to the torque-dependent portion of the required pressing force.
Applying load to the disks and/or conical disks that are associated with a disk set, respectively, causes the friction force between the plate-link chain and the respective disks to be sufficient for the respectively desired torque transmission. The forces acting, particularly axially, on the respective disks of a disk set are preferably controlled as a function of the torque to be transmitted and/or the adjusted transmission ratio, particularly relative to each individual disk set. In particular, on different disk sets different forces act in the axial direction on the disks of the disk sets.
The different disk sets are preferably associated with separate torque sensors. One torque sensor may possibly be associated with several disk sets, wherein transmission ratio devices are preferably incorporated in the transmitting section between the torque sensor and the respective disk sets that in that case can be differently configured and can be controlled.
In a preferred embodiment, a disk set of the continuously variable transmission is associated with a torque sensor that controls the pressing force on that disk set, while on the other disk set the pressing force is controlled in a different manner, e.g., through a spindle or similar device.
The continuously variable transmission can also have a different design.
In a particularly preferred embodiment, the torque sensor has the design of a mechanical torque sensor. In a particularly preferred embodiment, load is applied to the disk set through the torque sensor via mechanical components that interact with each other without providing a pressure fluid in the transmitting section.
In accordance with the invention, a continuously variable transmission is equipped with at least one torque sensor as well as with a device that ensures that the power transmission between an input member and an output member of the torque sensor takes place basically in the radial position that corresponds to the travel radius of an endless, torque-transmitting means that is incorporated on the disk set that is associated with that torque sensor. That power transmission is effected especially through a transmitting device, such as a ball or similar.
The invention particularly provides for the fact that a signal that indicates that the transmission ratio of the continuously variable transmission should be changed is generated for the purpose of controlling a torque sensor or for controlling a continuously variable transmission having a torque sensor under defined circumstances. The transmission ratio of that continuously variable transmission is changed as a function of that signal, particularly by changing the respective axial spacings of the disks that are associated with the respective disk sets of that transmission. In particular, that causes the radial position of an endless, torque-transmitting means that extends around the disk sets, to be changed as a function of the slope of the respective disks. In accordance with the invention, it is ensured that a transmitting element that can transmit power and/or torque between an input member and an output member of a torque sensor, is arranged, respectively, in the radial position, in which the endless, torque-transmitting means is arranged on one of those disk sets. That disk set is especially a disk set that is associated with the appropriate torque sensor.
Preferably, one torque sensor is associated with each of the disk sets of the continuously variable transmission, wherein with an appropriate adjustment of those disk sets it is ensured that a transmitting element of the respective torque sensor is held in the radial position, in which the endless, torque-transmitting means extends around the associated disk set.
In accordance with the present invention, the term xe2x80x9ccontrollingxe2x80x9d should be interpreted particularly as xe2x80x9cregulatingxe2x80x9d and/or xe2x80x9ccontrollingxe2x80x9d pursuant to DIN (German Industry Standard). The same applies to terms derived from the term xe2x80x9ccontrolling.xe2x80x9d
The following description explains the invention and/or the aspects of the invention more closely based upon the drawing figures, which description is not intended to limit the scope of the invention.